Antimicrobial resistance is one of the most serious threats to human and animal health. Evidence suggests that the overuse of antimicrobial agents in animal production has led to the emergence and dissemination of multidrug-resistant isolates. The objective of this study was to assess the rate of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in calf feces and to characterize their resistance genes for antibiotics like beta-lactams and colistin, but also to determine their virulence genes. Fecal samples were collected from 100 diarrheic calves in the region of Bizerte, Tunisia. After isolation, E. coli isolates were screened for antimicrobial resistance against 21 antibiotics by the disc diffusion method. Characterization of β-lactamase genes and determination of associated resistance genes were performed by polymerase chain reaction. Among 71 E. coli isolates, 26 (36.6%) strains were ESBL-producing. Most of these isolates were multidrug-resistant (92.3%) and the most prevalent beta-lactamase genes detected were bla_CTX-M (n = 26), bla_SHV (n = 11), and bla_TEM (n = 8), whereas only 1 isolate carried the bla_CMY gene. In addition, resistance to carbapenems was detected in two isolates; one of them harbored both bla_OXA-48 and bla_IMP genes and the other isolate carried only the bla_IMP gene. Several resistance genes were identified for the first time in Tunisia from cases of diarrheic calves. Furthermore, to the best of our knowledge, this is the first report of detection and identification of carbapenem resistance genes and virulence genes from calves in North Africa. A high occurrence of antimicrobial resistance of E. coli recovered from fecal samples of calves with diarrhea was observed, highlighting the need for prudent use of antimicrobial agents in veterinary medicine to decrease the incidence of multidrug-resistant bacteria for both animals and humans.

中文翻译：

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突尼斯腹泻犊牛产超广谱 β-内酰胺酶大肠杆菌中 OXA-48 和 IMP 基因的首次报告

抗菌素耐药性是人类和动物健康面临的最严重威胁之一。有证据表明，在动物生产中过度使用抗菌剂导致了多重耐药菌株的出现和传播。本研究的目的是评估小牛粪便中产生超广谱 β-内酰胺酶 (ESBL) 的大肠杆菌的比率，并表征它们对 β-内酰胺和粘菌素等抗生素的耐药基因，同时确定它们的毒力基因。从突尼斯比塞大地区的 100 头腹泻小牛身上采集粪便样本。分离后，大肠杆菌通过纸片扩散法筛选分离株对 21 种抗生素的耐药性。β-内酰胺酶基因的表征和相关抗性基因的测定通过聚合酶链反应进行。在 71 个大肠杆菌分离株中，26 个 (36.6%) 菌株产 ESBL。这些分离株中的大多数具有多重耐药性 (92.3%)，检测到的最普遍的 β-内酰胺酶基因是bla _CTX-M ( n  = 26)、bla _SHV ( n  = 11) 和bla _TEM ( n  = 8)，而只有 1 个分离株携带bla _CMY基因。此外，在两个分离株中检测到对碳青霉烯类的耐药性；其中一个同时携带bla _OXA-48和bla _IMP基因，而另一个分离株仅携带bla _IMP基因。在突尼斯，首次从腹泻小牛病例中鉴定出几种抗性基因。此外，据我们所知，这是北非犊牛碳青霉烯类抗性基因和毒力基因检测和鉴定的首份报告。大肠杆菌耐药性高发观察到从患有腹泻的小牛的粪便样本中回收的抗生素，突出表明需要在兽医学中谨慎使用抗菌剂，以减少动物和人类的多重耐药细菌的发生率。